Comments by Jan

  • Servo control interface in detail

    Servo control interface in detail

    - 14 May 2018

    Your questions are answered in the rest of the post and other screenshots. When the servo gets the control signal pulse, it sends a pulse of power to the motor based on how big the error is. The energizing of the motor (the current pulse) is not ending because the error went away. You can see in the last screenshot that once the servo is in position with no resistance, there are no current spikes corresponding to the control pulses (the last two).

    - Jan

  • New product: VL53L0X Time-of-Flight Distance Sensor Carrier

    New product: VL53L0X Time-of-Flight Distance Sensor Carrier

    - 3 April 2018

    Hello, Santiago.

    Yes, we are planning on that. We have the sensor chip on order, but with the crazy lead times lately, it might still be a few months before we get them.

    - Jan

  • New product: Pololu USB AVR Programmer v2.1

    New product: Pololu USB AVR Programmer v2.1

    - 23 March 2018

    Hi, Brian.

    Please keep in mind this is just an issue when powering the A-Star from the programmer, so the programmer still works fine if the A-Star has its own power source, which you typically have to have, anyway. But it can be convenient, which is why we improved the feature. There are some tricks you can do, like increasing the capacitance on the programmer side or putting a small resistor in line with the power from the programmer to the A-Star. It's not something we would want to do for a production solution.

    In any case, I want your reaction to be, "yay!", not "darn!" when we make better products. If you email us with your order number and reference this comment, we'll send you a couple of the new ones.

    - Jan

  • New products: RoboClaw Solo 30A and 60A Motor Controllers

    New products: RoboClaw Solo 30A and 60A Motor Controllers

    - 19 March 2018

    Hi, Jay.

    What prices, for which controllers, would you consider not to be "so much"? And if you have some reasons for your prices, please share those as that would also help us give you a better answer.

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 13 March 2018

    Hi, Robert.

    It sounds like you are trying to put your cells in parallel, which can be tricky, to get a 1.2V, 100Ah pack, and then to somehow boost to 12V, which is going to be very difficult and inefficient. You would be better off putting your cells in series, which gets you straight to 12V, and then the only question is whether the D cells can give you 50A. I don't think they can, and you say you saw 30A peak, which sounds plausible to me. So if you really need 50A, you should figure out how to put the two 10-cell packs in parallel (which, again, is tricky, since you're initially shorting two different packs together). If you need a regulated 12V, you could do 20 or more cells in series to get to about 24V, then regulate that down to 12V. I don't know where to get a 50A 12V regulator that can take 40V in, but it will be way more efficient than trying to boost 1.2V to 12V.

    Separately, why don't you just use a 12V gel cell (lead acid) battery? It's pretty easy to get them with about 10-15Ah capacity, which should be able to do 50A peaks pretty easily, and it wouldn't be much bigger or heavier than a NiMH battery.

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 26 February 2018

    Hi, David.

    Did you read the main post? It looks like you did not get the point of the amp vs. amp-hour distinction. (Or maybe it's just a typo in what you posted for your battery spec.)

    In any case, if the battery is lasting a week, it's probably good enough. The main problem is that you are trying to use more energy in your lights overnight than you collect during the day. If you want to use 18W for eight hours and you have only 4 hours to collect that, you would need at least 36W. That would be at 100% efficiency, which for sure you will not have, and for the whole time, not just when you get the most direct sunlight. You probably need at least five times your current solar panel capacity.

    - Jan

  • How I picked our new machines (and what they mean for you!)

    How I picked our new machines (and what they mean for you!)

    - 14 February 2018

    Thanks. The bottom-side solder does become liquid again when the board goes through the oven a second time, but the surface tension of the solder keeps the components from falling off. What components we put on the side that goes through twice is something we consider when designing a board since something really heavy could fall off, and some components are better not to put through the oven twice. I don't think the solder joint quality is meaningfully affected by the second reflow cycle.

    - Jan

  • Continuous-rotation servos and multi-turn servos

    Continuous-rotation servos and multi-turn servos

    - 5 February 2018

    Hi, John.

    Either of those routes will probably work, and it doesn't sound very expensive to try. 5k-50k is probably ok for the pot resistance. Let us know how it turns out!

    - Jan

  • New adjustable voltage regulators with multi-turn fine adjustment

    New adjustable voltage regulators with multi-turn fine adjustment

    - 8 January 2018

    Thanks for the feedback. That higher output range you are asking for is not feasible on this particular design. Do you need the 3-16V input range in the same device, or are you wanting the higher output voltage for an application where the input voltage range would be smaller? (I'm asking because it's much easier to make just a step-up converter for low input voltage applications, and the step down/step up (or even straight step down) functionality would be easier to achieve if it did not have to operate at so low of a voltage.)

    - Jan

  • Understanding battery capacity: Ah is not A

    Understanding battery capacity: Ah is not A

    - 18 December 2017

    Hi, Cindy.

    Your math generally seems right, though the "56 mA per use" is not correct; it's that times the two minutes to get back to units for total capacity. But the 56 mA is probably a more useful figure, as long as you realize it's not "per use" but the average rate over the two minutes. Maybe the motor only runs for 10% of that, and the remaining time the current is negligible, so the peak current draw might be over half an amp but only for ten seconds.

    It sounds like the 5V, 1A adapter will likely be sufficient. In general, it's fine to use a bigger adapter since it's not going to force the currrent into your system.

    - Jan

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